The present disclosure relates generally to well drilling operations and, more particularly, to ranging measurements using modulated signals.
In certain instances, such as in a blowout, it may be necessary to intersect a first well, called a target well, with a second well, called a relief well. The second well may be drilled for the purpose of intersecting the target well, for example, to relieve pressure from the blowout well. Since traditional survey measurements have cones of uncertainty much larger than the size of the target, contacting the target well with the relief well typically requires multiple downhole measurements to identify the precise location of the target well. These downhole measurements may include transmitting a time-varying signal into a formation and measuring any resultant magnetic field that is induced on the target well. Typically, the time-varying signal is a sinusoid. It can be difficult to identify the precise direction of a target well from sinusoidal signal, however, due to sign variations in the resultant magnetic field.
While embodiments of this disclosure have been depicted and described and are defined by reference to exemplary embodiments of the disclosure, such references do not imply a limitation on the disclosure, and no such limitation is to be inferred. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and not exhaustive of the scope of the disclosure.